U.S. patent application number 11/697315 was filed with the patent office on 2007-10-11 for method of producing low viscosity phenol-modified aromatic hydrocarbon formaldehyde resin.
Invention is credited to Seiji Kita, Masashi Ogiwara.
Application Number | 20070238850 11/697315 |
Document ID | / |
Family ID | 38513665 |
Filed Date | 2007-10-11 |
United States Patent
Application |
20070238850 |
Kind Code |
A1 |
Ogiwara; Masashi ; et
al. |
October 11, 2007 |
Method of Producing Low Viscosity Phenol-Modified Aromatic
Hydrocarbon Formaldehyde Resin
Abstract
Provided is a method of producing a low viscosity
phenol-modified aromatic hydrocarbon formaldehyde resin (C),
including subjecting an aromatic hydrocarbon formaldehyde resin (A)
and a phenol (B) to condensation reaction under the presence of an
acid catalyst. The method includes: terminating, when a reaction
mixture has a viscosity at 25.degree. C. of 200 to 1,500 mPaS, the
condensation reaction by adding an inorganic basic compound and/or
a tertiary amine compound having a boiling point of 300.degree. C.
or more; and distilling and removing the phenol (B) unreacted and a
low boiling component after termination of the condensation
reaction, whereby there can be produced a low viscosity
phenol-modified aromatic hydrocarbon formaldehyde resin which is
kept in a liquid state and contains small amounts of unreacted
phenols, and in which increase in viscosity is small even after
removal of low boiling components.
Inventors: |
Ogiwara; Masashi; (Okayama,
JP) ; Kita; Seiji; (Okayama, JP) |
Correspondence
Address: |
ANTONELLI, TERRY, STOUT & KRAUS, LLP
1300 NORTH SEVENTEENTH STREET, SUITE 1800
ARLINGTON
VA
22209-3873
US
|
Family ID: |
38513665 |
Appl. No.: |
11/697315 |
Filed: |
April 6, 2007 |
Current U.S.
Class: |
528/129 |
Current CPC
Class: |
C08G 8/28 20130101; C08G
8/30 20130101 |
Class at
Publication: |
528/129 |
International
Class: |
C08G 14/02 20060101
C08G014/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 7, 2006 |
JP |
2006-106287 |
Claims
1. A method of producing a low viscosity phenol-modified aromatic
hydrocarbon formaldehyde resin, including subjecting an aromatic
hydrocarbon formaldehyde resin (A) and a phenol (B) to condensation
reaction under the presence of an acid catalyst to obtain a low
viscosity phenol-modified aromatic hydrocarbon formaldehyde resin
(C), the method comprising the steps of: terminating, when a
reaction mixture has a viscosity at 25.degree. C. of 200 to 1,500
mPaS, the condensation reaction by adding an inorganic basic
compound and/or a tertiary amine compound having a boiling point of
300.degree. C. or more; and distilling and removing the phenol (B)
unreacted and a low boiling component after termination of the
condensation reaction.
2. The method of producing a low viscosity phenol-modified aromatic
hydrocarbon formaldehyde resin according to claim 1, wherein: the
aromatic hydrocarbon formaldehyde resin (A) comprises at least one
kind selected from the group consisting of a xylene formaldehyde
resin, a mesitylene formaldehyde resin, and a toluene formaldehyde
resin; and the viscosity at 25.degree. C. is 30 to 500 mPaS.
3. The method of producing a low viscosity phenol-modified aromatic
hydrocarbon formaldehyde resin according to claim 1, wherein: the
acid catalyst comprises para-toluene sulfonic acid; the aromatic
hydrocarbon formaldehyde resin (A) comprises a xylene formaldehyde
resin or a mesitylene formaldehyde resin; and the acid catalyst is
added in an amount of 5 to 50 ppm with respect to a total amount of
the aromatic hydrocarbon formaldehyde resin (A) and the phenol
(B).
4. The method of producing a low viscosity phenol-modified aromatic
hydrocarbon formaldehyde resin according to claim 1, wherein: the
acid catalyst comprises para-toluene sulfonic acid; the aromatic
hydrocarbon formaldehyde resin (A) comprises a toluene formaldehyde
resin; and the acid catalyst is added in an amount of 50 to 500 ppm
with respect to a total amount of the toluene formaldehyde resin
and the phenol (B).
5. The method of producing a low viscosity phenol-modified aromatic
hydrocarbon formaldehyde resin according to claim 1, wherein the
inorganic basic compound comprises at least one kind selected from
the group consisting of sodium hydroxide, sodium carbonate,
potassium hydroxide, and calcium hydroxide.
6. The method of producing a low viscosity phenol-modified aromatic
hydrocarbon formaldehyde resin according to claim 1, wherein the
tertiary amine compound having a boiling point of 300.degree. C. or
more comprises triethanolamine.
7. The method of producing a low viscosity phenol-modified aromatic
hydrocarbon formaldehyde resin according to claim 1, wherein a
weight ratio between the aromatic hydrocarbon formaldehyde resin
(A) and the phenol (B) (the aromatic hydrocarbon formaldehyde resin
(A):the phenol (B)) is 95:5 to 60:40.
8. The method of producing a low viscosity phenol-modified aromatic
hydrocarbon formaldehyde resin according to claim 1, wherein the
low viscosity phenol-modified aromatic hydrocarbon formaldehyde
resin (C) has a viscosity at 25.degree. C. of 1,500 to 10,000
mPaS.
9. The method of producing a low viscosity phenol-modified aromatic
hydrocarbon formaldehyde resin according to claim 1, wherein, in
the step of distilling and removing the unreacted phenol (B) and
the low boiling component after the termination of the condensation
reaction, the collected unreacted phenol (B) and the collected low
boiling component are reused as a part of a reaction raw
material.
10. The method of producing a low viscosity phenol-modified
aromatic hydrocarbon formaldehyde resin according to claim 1,
wherein the low viscosity phenol-modified aromatic hydrocarbon
formaldehyde resin (C) comprises the unreacted phenol (B) in a
content of 0.5% by weight or less.
11. The method of producing a low viscosity phenol-modified
aromatic hydrocarbon formaldehyde resin according to claim 1,
wherein the condensation reaction is performed at a reaction
temperature of 120 to 200.degree. C. for 1 to 6 hours.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method of producing a low
viscosity phenol-modified aromatic hydrocarbon formaldehyde resin
containing a specific amount or more of skeletons of phenols
therein.
BACKGROUND ART
[0002] Aromatic hydrocarbon formaldehyde resins are obtained by
reaction between aromatic hydrocarbons and formalin under the
presence of acid catalysts, and have excellent compatibility to
various natural resins and synthetic resins. Thus, the aromatic
hydrocarbon formaldehyde resins are mixed with the various natural
resins and synthetic resins as main resins for improving adhesion
property, humidity resistance, and electrical characteristics of
the main resins. Further, the aromatic hydrocarbon formaldehyde
resins can be used after being modified with phenols to
additionally improve the properties.
[0003] Many of conventional phenol-modified aromatic hydrocarbon
formaldehyde resins are solid or have high viscosity. As a method
of improving operability of the resins, there is used a method of
subjecting the resins to dilution treatment with organic solvents.
However, the method has problems in that an additionally large
apparatus is required in the dilution treatment with the organic
solvents, use of the solvents tends to be strictly restricted from
a viewpoint of environmental problems, and the like. Accordingly,
there is a demand for a phenol-modified aromatic hydrocarbon
formaldehyde resin which has low viscosity and requires no dilution
treatment with the organic solvents.
[0004] As a method of obtaining a low viscosity phenol-modified
aromatic hydrocarbon formaldehyde resin, there is a method
involving reaction in a reaction system having excessive amounts of
phenols, but the method is not preferable because large amounts of
unreacted phenols remain in the resultant resin. Further, even when
the unreacted phenols are removed therefrom, the resin is
semi-solid at room temperature, resulting in a problem in
operability of the resin.
[0005] In Patent Document 1, for example, there is disclosed
modification of an aromatic hydrocarbon formaldehyde resin with
small amounts of phenols by using as a weak acid catalyst an amine
salt of para-toluene sulfonic acid. However, in a case where
unreacted phenols and unreacted low boiling components are
distilled and removed by a distillation operation for ameliorating
loss on heating, the reaction proceeds even during the distillation
operation and the viscosity of the resin increases. Further, in a
case where collected unreacted phenols and unreacted low boiling
components are returned to the reaction system, there arises a
problem in that components derived from the amine of the amine salt
of para-toluene sulfonic acid act as a reaction terminator, so a
circulating type production cycle cannot be established.
[0006] Patent Document 1: Japanese Patent Application Laid-Open No.
2003-119234
DISCLOSURE OF THE INVENTION
Problem to be Solved by the Invention
[0007] It is an object of the present invention to provide a method
of producing a low viscosity liquid phenol-modified aromatic
hydrocarbon formaldehyde resin, which can ameliorate the
above-mentioned problems of the conventional low viscosity
phenol-modified aromatic hydrocarbon formaldehyde resins.
Means for Solving the Problems
[0008] The inventors of the present invention have made extensive
studies to solve the above-mentioned problems. As a result, the
inventors of the present invention have found that a low viscosity
phenol-modified aromatic hydrocarbon formaldehyde resin which is
kept in a liquid state and contains small amounts of unreacted
phenols, and in which increase in viscosity is small even after
removal of low boiling components can be obtained by using an
aromatic hydrocarbon formaldehyde resin and adding thereto a basic
compound and/or a tertiary amine compound having a boiling point of
300.degree. C. or more to terminate condensation reaction, and thus
the present invention has been achieved.
[0009] That is, according to the present invention, there is
provided a method of producing a low viscosity phenol-modified
aromatic hydrocarbon formaldehyde resin, including subjecting an
aromatic hydrocarbon formaldehyde resin (A) and a phenol (B) to
condensation reaction under the presence of an acid catalyst to
obtain a low viscosity phenol-modified aromatic hydrocarbon
formaldehyde rein (C), the method including the steps of:
terminating, when a reaction mixture has a viscosity at 25.degree.
C. of 200 to 1,500 mPaS, the condensation reaction by adding an
inorganic basic compound and/or a tertiary amine compound having a
boiling point of 300.degree. C. or more; and distilling and
removing the phenol (B) unreacted and a low boiling component after
termination of the condensation reaction.
EFFECTS OF THE INVENTION
[0010] According to the production method of the present invention,
there can be obtained a low viscosity phenol-modified aromatic
hydrocarbon formaldehyde resin which is kept in a liquid state and
contains small amounts of unreacted phenols, and in which increase
in viscosity is small even after removal of low boiling
components.
[0011] The low viscosity aromatic hydrocarbon formaldehyde resin
obtained by the present invention contains a phenolic hydroxyl
group, has a low viscosity, has excellent compatibility with an
epoxy resin, a curing agent thereof, and a urethane resin, and
exhibits excellent anticorrosive property and excellent surface
smoothness when used as an additive for an epoxy resin-based heavy
duty coating.
BEST MODE FOR CARRYING OUT THE INVENTION
[0012] The aromatic hydrocarbon formaldehyde resin (A) is generally
obtained by subjecting an aromatic hydrocarbon such as metaxylene
or mesitylene to reaction with formalin under the presence of an
acid catalyst under reflux for 2 to 8 hours. An aromatic
hydrocarbon formaldehyde resin obtained by using xylene is referred
to as a xylene formaldehyde resin, and that obtained by using
mesitylene is referred to as a mesitylene formaldehyde resin.
Examples of raw materials for the aromatic hydrocarbon formaldehyde
resin (A) to be used in the present invention include toluene, 3
isomers of xylene, mesitylene, pseudocumene, a monocyclic aromatic
hydrocarbon compound having 10 or more carbon atoms, and a
polycyclic aromatic hydrocarbon compound such as naphthalene or
methylnaphthalene. Note that a mixture of two or more of the
aromatic hydrocarbons can be used.
[0013] The aromatic hydrocarbon formaldehyde resin (A) to be used
in the present invention has a viscosity at 25.degree. C. of
preferably 30 to 500 mPaS, and more preferably 50 to 200 mPaS. The
aromatic hydrocarbon formaldehyde resin having a relatively low
viscosity as described above can be synthesized by, as described in
Japanese Patent Application Laid-Open No. 10-168147, subjecting an
aromatic hydrocarbon and formaldehyde to reaction with an addition
of alcohols such as methanol under the presence of a strong acid
catalyst such as sulfuric acid.
[0014] The aromatic hydrocarbon formaldehyde resin (A) is mainly
composed of a compound which has 1 to 8 of aromatic nuclei (1 to 8
nuclides) in which the aromatic nuclei have a methylene bond, a
dimethylene-ether bond, and an acetal bond therebetween, and an
aromatic nucleus at the end of its molecule has a methylol group,
an acetal group, and a methoxymethyl group. The aromatic
hydrocarbon formaldehyde resin (A) is known to react with a
compound having a hydroxyl group, a carboxyl group, or the like,
such as a phenol or a third component such as an aliphatic or
aromatic carboxylic acid. In the present invention, the aromatic
hydrocarbon formaldehyde resin (A) is reacted with the phenol (B)
to obtain the phenol-modified aromatic hydrocarbon formaldehyde
resin (C).
[0015] Examples of the phenols (B) to be used in the present
invention include phenol, cresols, xylenols, butylphenol,
octylphenol, nonylphenol, cardanol, and terpene phenol, with phenol
being preferable. One of the phenols (B) may be used alone, or a
mixture of two or more of them.
[0016] Examples of the acid catalyst to be used in the present
invention include sulfuric acid, hydrochloric acid, para-toluene
sulfonic acid, and oxalic acid, with para-toluene sulfonic acid
being preferable. When the aromatic hydrocarbon formaldehyde resin
(A) is a xylene formaldehyde resin or a mesitylene formaldehyde
resin, para-toluene sulfonic acid is added in an amount of
preferably 5 to 50 ppm, and more preferably 10 to 30 ppm with
respect to a total amount of the aromatic hydrocarbon formaldehyde
resin (A) and the phenol (B). An amount of less than 5 ppm is not
preferable because the reaction proceeds slowly, and an amount
exceeding 50 ppm is not preferable because the reaction proceeds
locally, resulting in gelation. When the aromatic hydrocarbon
formaldehyde resin (A) is a toluene formaldehyde resin,
para-toluene sulfonic acid is added in an amount of preferably 50
to 500 ppm, and more preferably 100 to 300 ppm with respect to the
total amount of the toluene formaldehyde resin and the phenol (B).
An amount of less than 50 ppm is not preferable because the
reaction proceeds slowly, and an amount exceeding 500 ppm is not
preferable from an economical viewpoint because it does not affect
the promotion of the reaction.
[0017] A blending ratio between the aromatic hydrocarbon
formaldehyde resin (A) and the phenol (B) is preferably 95:5 to
60:40, and more preferably 90:10 to 70:30 in terms of weight ratio.
When the blending ratio of the phenol (B) is too large, the amount
of an unreacted phenol (B) increases and a large burden is applied
to the distillation operation. In addition, a small amount of the
phenol (B) is not preferable because the anticorrosive property and
adhesion strength in coating application decrease and an effect of
phenol modification decreases.
[0018] A reaction temperature and a reaction time vary depending on
the kind of the phenol (B) to be used and the kind and amount of
the acid catalyst, but it is preferable that the reaction
temperature be about 120 to 200.degree. C. and the reaction time be
about 1 to 6 hours. When phenol is used as the phenol (B), it is
preferable that the reaction temperature be about 160 to
180.degree. C. and the reaction time be about 1 to 3 hours.
[0019] Timing at which the condensation reaction is terminated can
be determined by measuring a viscosity of a reaction mixture or a
content of the unreacted phenols in the reaction mixture. The
timing at which the condensation reaction is terminated is
preferably determined by measuring the viscosity of the reaction
mixture. When the condensation reaction is to be terminated, the
reaction mixture has a viscosity at 25.degree. C. of 200 to 1,500
mPaS, and preferably 400 to 1,000 mPaS. The viscosity exceeding
1,500 mPaS is not preferable because a high viscosity is imparted
to a product obtained after distillation, so smoothness in the
coating application is deteriorated. The viscosity of less than 200
mPaS is not preferable because of insufficient reaction.
[0020] In the step of terminating the reaction, an inorganic basic
compound or a tertiary amine compound is preferably used as the
basic compound to be added as the reaction terminator. Examples of
the inorganic basic compound include sodium hydroxide, sodium
carbonate, potassium hydroxide, and calcium hydroxide. Since a
tertiary amine compound having a low boiling point is distilled out
in the distillation operation, a tertiary amine compound having a
boiling point of 300.degree. C. or more is used as the tertiary
amine compound to be used in the present invention, and triethanol
amine is particularly preferable.
[0021] The inorganic basic compound or the tertiary amine compound
is added in an amount of preferably 1 to 5 times in molar quantity,
and more preferably 2 to 3 times in molar quantity with respect to
the amount of the acid catalyst to be used.
[0022] The inorganic basic compound is preferably added in a form
of an aqueous solution or an alcohol solution. The tertiary amine
compound is preferably added directly.
[0023] The content of the unreacted phenol (B) when the
condensation reaction is terminated is preferably 2 to 5% by
weight.
[0024] The basic compound is added to terminate the condensation
reaction, and after the termination of the condensation reaction, a
step of distilling and removing the unreacted phenol (B) and low
boiling components is performed, whereby the content of the
unreacted phenol (B) in the phenol-modified aromatic hydrocarbon
formaldehyde resin (C) can be reduced. It is preferable that the
content of the unreacted phenol (B) be 0.5% by weight or less.
[0025] As a method of distilling and removing the unreacted phenol
(B) and the low boiling components, there may be adopted a method
of distilling and removing them under vacuum of about 1.3 to 4 kPa
(10 to 30 Torr), or a method of distilling and removing them by
steam distillation. The method of distilling and removing them
under vacuum is preferable. The thus-collected low boiling
components contain substances having reactive functional groups,
and the collected unreacted phenol (B) and low boiling components
can be reused as a part of a reaction raw material. By the
above-mentioned method, waste water treatment can be relieved and a
basic unit can be improved.
[0026] The low viscosity phenol-modified aromatic hydrocarbon
formaldehyde resin (C) obtained by the present invention can be
controlled to have a viscosity at 25.degree. C. of 1,500 to 10,000
mPaS after the unreacted phenol (B) and the low boiling components
are distilled and removed by controlling the viscosity of the
reaction mixture at the time when the condensation reaction is to
be terminated.
EXAMPLES
[0027] Hereinafter, the present invention will be described in
detail by referring to examples. Note that the term "%" denotes "%
by weight" unless otherwise stated. Methods of evaluating the low
viscosity phenol-modified aromatic hydrocarbon formaldehyde resin
are described hereinbelow.
(1) Viscosity
[0028] The viscosity at 25.degree. C. was measured by using a TV20
type cone-plate viscometer.
(2) Content of Unreacted Phenol
[0029] 2 g of a sample was collected and dissolved in 20 ml of
acetone, and the mixture was added with 0.1 g of methyl benzoate as
an inner standard sample to prepare a sample for analysis. 0.5
.mu.ml of the sample for analysis was subjected to measurement by
an inner standard method at a column temperature of gas
chromatography of 120.degree. C.
Example 1
[0030] A 2-L separable flask equipped with a thermometer, a Liebig
condenser, a stirrer, and a nitrogen introduction tube was added
with 850 g of a xylene formaldehyde resin (NIKANOL (trade name)
Y100, manufactured by mitsubishi Gas Chemical Company, Inc.) having
a viscosity at 25.degree. C. of 100 mPaS, 150 g of phenol (special
grade, manufactured by Wako Pure Chemical Industries, Ltd.), and
2.4 ml of a 0.5% aqueous solution of para-toluene sulfonic acid
(special grade, manufactured by Wako Pure Chemical Industries,
Ltd.) (12 ppm with respect to a total amount of the xylene
formaldehyde resin and phenol). Reaction was allowed to proceed for
2 hours at 165.degree. C. under a nitrogen flow, and the viscosity
at 25.degree. C. of the reaction mixture was measured to be 650
mPaS. The reaction mixture was added with 1.4 ml of a 0.5% aqueous
solution of potassium hydroxide (an amount 2 times equimolar with
respect to an amount of a catalyst) to terminate the reaction. The
content of the unreacted phenol at the time when the condensation
reaction was terminated was 4.8%. The temperature was increased to
180.degree. C. under vacuum pressure (2.7 kPa) to distill the
unreacted phenol and low boiling components out, thereby obtaining
880 g of a phenol-modified xylene formaldehyde resin having a
viscosity at 25.degree. C. of 7,400 mPaS and a content of the
unreacted phenol of 0.3%. A fraction collected by the distillation
weighed 103 g.
Example 2
[0031] A 2-L separable flask equipped with a thermometer, a Liebig
condenser, a stirrer, and a nitrogen introduction tube was added
with 850 g of a xylene formaldehyde resin (NIKANOL (trade name)
Y100, manufactured by mitsubishi Gas Chemical Company, Inc.) having
a viscosity at 25.degree. C. of 100 mPaS, 150 g of phenol, 100 g of
a liquid mixture of the unreacted phenol and unreacted low boiling
components which had been collected by distillation in Example 1,
and 2.6 ml of a 0.5% aqueous solution of para-toluene sulfonic acid
(13 ppm with respect to a total amount of the xylene formaldehyde
resin and phenol). Reaction was allowed to proceed for 2 hours at
165.degree. C. under a nitrogen flow, and the viscosity at
25.degree. C. of the reaction mixture was measured to be 450 mPaS.
The reaction mixture was added with 1.5 ml of a 0.5% aqueous
solution of potassium hydroxide (an amount 2 times equimolar with
respect to an amount of a catalyst) to terminate the reaction. The
content of the unreacted phenol at the time when the condensation
reaction was terminated was 4.5%. The temperature was increased to
180.degree. C. under vacuum pressure (2.7 kPa) to distill the
unreacted phenol and low boiling components out, thereby obtaining
890 g of a phenol-modified xylene formaldehyde resin having a
viscosity at 25.degree. C. of 3,800 mPaS and a content of the
unreacted phenol of 0.3%. A fraction collected by the distillation
weighed 107 g.
Example 3
[0032] A 2-L separable flask equipped with a thermometer, a Liebig
condenser, a stirrer, and a nitrogen introduction tube was added
with 750 g of a xylene formaldehyde resin (NIKANOL (trade name)
Y100, manufactured by mitsubishi Gas Chemical Company, Inc.) having
a viscosity at 25.degree. C. of 100 mPaS, 250 g of phenol, 100 g of
a liquid mixture of the unreacted phenol and unreacted low boiling
components which had been collected by distillation in Example 2,
and 6ml of a 0.5% aqueous solution of para-toluene sulfonic acid
(30 ppm with respect to a total amount of the xylene formaldehyde
resin and phenol). Reaction was allowed to proceed for 1.5 hours at
165.degree. C. under a nitrogen flow, and the viscosity at
25.degree. C. of the reaction mixture was measured to be 750 mPaS.
The reaction mixture was added with 3.5 ml of a 0.5% aqueous
solution of sodium hydroxide (an amount 2 times equimolar with
respect to an amount of a catalyst) to terminate the reaction. The
content of the unreacted phenol at the time when the condensation
reaction was terminated was 4.9%. The temperature was increased to
180.degree. C. under vacuum pressure (2.7 kPa) to distill the
unreacted phenol and low boiling components out, thereby obtaining
880 g of a phenol-modified xylene formaldehyde resin having a
viscosity at 25.degree. C. of 7,800 mPaS and a content of the
unreacted phenol of 0.3%. A fraction collected by the distillation
weighed 108 g.
Example 4
[0033] A 2-L separable flask equipped with a thermometer, a Liebig
condenser, a stirrer, and a nitrogen introduction tube was added
with 850 g of a mesitylene formaldehyde resin (NIKANOL (trade name)
Y51, manufactured by Mitsubishi Gas Chemical Company, Inc.) having
a viscosity at 25.degree. C. of 50 mPaS, 150 g of phenol, and 2.4
ml of a 0.5% aqueous solution of para-toluene sulfonic acid (12 ppm
with respect to a total amount of the mesitylene formaldehyde resin
and phenol). Reaction was allowed to proceed for 2 hours at
165.degree. C. under a nitrogen flow, and the viscosity at
25.degree. C. of the reaction mixture was measured to be 550 mPaS.
The reaction mixture was added with 1.4 ml of a 0.5% aqueous
solution of potassium hydroxide (an amount 2 times equimolar with
respect to an amount of a catalyst) to terminate the reaction. The
content of the unreacted phenol at the time when the condensation
reaction was terminated was 4.3%. The temperature was increased to
180.degree. C. under vacuum pressure (2.7 kPa) to distill the
unreacted phenol and low boiling components out, thereby obtaining
860 g of a phenol-modified mesitylene formaldehyde resin having a
viscosity at 25.degree. C. of 3,400 mPaS and a content of the
unreacted phenol of 0.3%. A fraction collected by the distillation
weighed 103 g.
Example 5
[0034] A 2-L separable flask equipped with a thermometer, a Liebig
condenser, a stirrer, and a nitrogen introduction tube was added
with 800 g of a toluene formaldehyde resin (Epodil (registered
trademark), manufactured by Air Products and Chemicals, Inc.)
having a viscosity at 25.degree. C. of 100 mPaS, 200 g of phenol
(special grade, manufactured by Wako Pure Chemical Industries,
Ltd.), and 2 ml of a 5% aqueous solution of para-toluene sulfonic
acid (special grade, manufactured by Wako Pure Chemical Industries,
Ltd.) (100 ppm with respect to a total amount of the toluene
formaldehyde resin and phenol). Reaction was allowed to proceed for
3 hours at 165.degree. C. under a nitrogen flow, and the viscosity
at 25.degree. C. of the reaction mixture was measured to be 1,300
mPaS. The reaction mixture was added with 1.2 ml of a 5% aqueous
solution of potassium hydroxide (an amount 2 times equimolar with
respect to an amount of a catalyst) to terminate the reaction. The
content of the unreacted phenol at the time when the condensation
reaction was terminated was 2.1%. The temperature was increased to
180.degree. C. under vacuum pressure (2.7 kPa) to distill the
unreacted phenol and low boiling components out, thereby obtaining
880 g of a phenol-modified toluene formaldehyde resin having a
viscosity at 25.degree. C. of 1,600 mPaS and a content of the
unreacted phenol of 0.3%. A fraction collected by the distillation
weighed 105 g.
Comparative Example 1
[0035] A 2-L separable flask equipped with a thermometer, a Liebig
condenser, a stirrer, and a nitrogen introduction tube was added
with 850 g of a xylene formaldehyde resin (NIKANOL (trade name)
Y100, manufactured by mitsubishi Gas Chemical Company, Inc.) having
a viscosity at 25.degree. C. of 100 mPaS, 150 g of phenol, and 2 ml
of a 5% aqueous solution of a pyridinium salt of para-toluene
sulfonic acid (0.01% with respect to a total amount of the xylene
formaldehyde resin and phenol). Reaction was allowed to proceed for
2 hours at 165.degree. C. under a nitrogen flow, and no basic
compound was added. The viscosity at 25.degree. C. of the reaction
mixture at the time when the reaction was terminated was measured
to be 660 mPaS. The temperature was increased to 180.degree. C.
under vacuum pressure (2.7 kPa) to distill the unreacted phenol and
low boiling components out, thereby obtaining 880 g of a
phenol-modified xylene formaldehyde resin having a viscosity at
25.degree. C. of 14,000 mPaS and a content of the unreacted phenol
of 0.3%. A fraction collected by the distillation weighed 103
g.
[0036] Further, a 2-L separable flask equipped with a thermometer,
a Liebig condenser, a stirrer, and a nitrogen introduction tube was
added with 850 g of a xylene formaldehyde resin (NIKANOL (trade
name) Y100, manufactured by Mitsubishi Gas Chemical Company, Inc.)
having a viscosity at 25.degree. C. of 100 mPaS, 150 g of phenol,
100 g of a liquid mixture of the unreacted phenol and unreacted low
boiling components which had been collected by distillation in
Comparative Example 1, and 2.2 ml of a 5% aqueous solution of a
pyridinium salt of para-toluene sulfonic acid (0.01% with respect
to a total amount of the xylene formaldehyde resin and phenol).
Reaction was allowed to proceed for 2 hours at 165.degree. C. under
a nitrogen flow, and the viscosity at 25.degree. C. of the reaction
mixture at this time was measured to be 110 mPaS. A content of the
unreacted phenol was measured to be 14%, so the reaction did not
proceed.
INDUSTRIAL APPLICABILITY
[0037] According to the production method of the present invention,
there can be obtained a low viscosity phenol-modified aromatic
hydrocarbon formaldehyde resin which is kept in a liquid state and
contains small amounts of unreacted phenols, and in which increase
in viscosity is small even after removal of low boiling components.
Further, the low viscosity aromatic hydrocarbon formaldehyde resin
obtained by the production method of the present invention contains
a phenolic hydroxyl group, has a low viscosity, has excellent
compatibility with an epoxy resin, a curing agent thereof, and a
urethane resin, and exhibits excellent anticorrosive property and
excellent surface smoothness when used as an additive for an epoxy
resin-based heavy duty coating.
* * * * *